In view of the dangers associated with automobile travel, there is an ongoing need for enhanced automobile safety features. One possible area of increased automobile safety involves the vehicle's cruise control system. A cruise control system permits an operator to set a predetermined speed of travel and controls the vehicle to maintain the predetermined speed. However, as the vehicle approaches obstacles, such as other cars and pedestrians, driver attention and intervention are necessary to actuate the vehicle's brakes thus overriding the cruise control system and avoiding collisions.
To enhance the safety of cruise control systems, "intelligent" cruise control systems have been suggested. Intelligent cruise control systems typically include a detector for detecting obstacles in the path of the vehicle and a controller for actuating the vehicle's brakes and overriding the cruise control system in response to the detection of obstacles. Advantageously, intelligent cruise control systems can reduce the dependency on the driver for avoiding collisions.
Another possible area of increased automobile safety is in collision avoidance systems. Like intelligent cruise control systems, collision avoidance systems generally include a detector for detecting obstacles in the path of the vehicle and a controller for actuating the vehicle's brakes in response to detected obstacles in order to avoid collisions.
In both the intelligent cruise control and collision avoidance applications, it is necessary to provide a detector capable of accurately and reliably detecting objects in the path of the vehicle. Such a detector is sometimes referred to as a Forward Looking Sensor (FLS) and must be relatively insensitive to the relative location of the automobile and obstacles and environmental conditions, such as temperature, humidity, ice and rain.
Radar is a suitable technology for implementing an automotive FLS. One type of radar suitable for this purpose is Frequency Modulated Continuous Wave (FMCW) radar. In typical FMCW radar, the frequency of the transmitted CW signal linearly increases from a first predetermined frequency to a second predetermined frequency. FMCW radar has the advantages of high sensitivity, relatively low transmitter power and good range resolution.
As with any consumer product, extensive operational testing in a multitude of scenarios and under a multitude of conditions to verify the accuracy and reliability of the product is desirable and may be the subject of a government mandate. One way to test the detection performance of an automotive FLS is to mount the FLS to an automobile and drive the automobile around a test track which presents multiple scenarios and conditions to the FLS. The response of the FLS to each scenario and condition is measured to verify the accuracy of the detection. Such testing may be performed with or without closing the feedback loop to the vehicle braking system. However, in order to verify the detection performance of the FLS in a multitude of scenarios and conditions, the trial would likely require millions of miles of test driving. Moreover, if it is necessary or desirable to test each FLS, this method of testing an automotive FLS is not generally feasible due to cost, time and reproduceability considerations.